For CDMA 2000 1X system in the wireless communication field, most of voice calls and data service calls are in rate set 1 which has a basic rate of 9.6 kbps.
The forward channel of calls of rate set 1 in CDMA 2000 1X system includes Traffic Channel (TCH) and Supplemental Channel (SCH). The TCH includes Fundamental Channel (FCH) and Dedicated Control Channel (DCCH).
The radio configuration of forward channel includes two types: RC3 and RC4. With the same rate, the usage of Walsh resource by RC4 of forward channel is half of the usage of Walsh resource by RC3 of forward channel, thus leaving a bigger Walsh resource capacity. But on the other hand, RC3 achieves a higher spreading gain than RC4. Relatively speaking, RC3 can save power.
A comparison of effects of allocating RC3 and RC4 respectively to a forward channel is shown in the following table:
RadioSupportedEb/Noconfigu-SCH rates,Walsh Codedemodu-ration(unit:with aCodeModulationlationtypekbps)basic rateratemodethresholdRC39.6, 19.2,64-order1/4QuaternaryRelatively38.4, 76.8,phase shiftlow153.6keying(QPSK)RC49.6, 19.2,128-order1/2QPSK1~2 dB38.4, 76.8,higher153.6,than RC3307.2
Eb/No in the above table refers to Energy per bit/Noise spectral density.
Power resource and Walsh resource are two most important wireless resources in CDMA 2000 1X system and they are most likely to become limited resources due to the bottleneck effect. Whether the system is power resource limited or Walsh resource limited changes dynamically. Sometimes the system is power resource limited and sometimes the system is Walsh resource limited. Therefore, only when the usage of the two resources is balanced can the system capacity be maximized.
Allocation of RC types plays a vital role in balancing the two resources.
Allocation solution in prior art I:
Parameters are used to allocate RC types of forward channel for the 1X rate set 1 calls accessing the system. Either RC3 or RC4 is allocated. Every call accessing the system is fixedly allocated to a given RC type.
The inventor of the present invention finds that the disadvantages of the prior art I are as follows: (1) The given RC type may be incompatible to the current system resource limit, thus reducing the system capacity; (2) When the system resource limit changes, RC type allocation can not change correspondingly and the adaptability of the RC type allocation to the system is poor. As a result, reasonable and efficient usage of system resource may not be guaranteed.
Allocation solution in prior art II:
An RC type is fixedly allocated for a call type. Parameters are used to allocate RC types of forward channel respectively for 1X rate set 1 voice calls and data calls accessing the system.
Prior art II differs from prior art I in that RC types are respectively allocated for different call types. Because a data service call requires a large amount of Walsh resource, usually RC4 is more often allocated to the data service call.
Although in prior art II, corresponding RC types are allocated according to difference among resources occupied by different call types, due to dynamic change of the current system resource limit, prior art II has the same disadvantage as prior art I.